Fresh off his DTM title, the German delivered a strong rookie Formula One season, highlighted by his 10th-place, point-scoring finish at the Austrian Grand Prix and quintet of Q2 appearances in qualifying.
Wehrlein did seek an explanation from the team and was told the 2015 sessions factored in the decision to give Ocon the nod.
“I know the reasons why and it's something easy to change,” he told Autosport.
“It had nothing to do with performance.
“In the test something happened, something they were not happy, and that's it.
“They think Esteban is fitting better into the team - that's it.
“The decision had nothing to do with feedback or performance, but had something to do with how they were getting along with me, something on a personal side.
“I cannot change it anymore and I can just learn from it and do better in the future.”
Wehrlein has yet to confirm his 2017 plans and his name has featured prominently on the rumour mill in recent weeks.
The third option would see Wehrlein return for a second campaign at Manor, with racing director Dave Ryan and the British outfit keen to keep him for next year.